Wireless power transmitter and receiver, and method for transmitting emergency information in a wireless charging network

ABSTRACT

Control method of wireless power receiver that includes transmitting advertisement signal to search for wireless power transmitter; receiving, from wireless power transmitter, connection request signal to form connection between wireless power receiver and wireless power transmitter, wherein connection request signal corresponds to advertisement signal; receiving charging power from wireless power transmitter; detecting error state in wireless power receiver while receiving charging power; generating alert signal indicating error state; and transmitting alert signal to wireless power transmitter, wherein error state includes at least one of over-voltage state in which rectifier voltage of wireless power receiver is greater than reference voltage, over-current state in which rectifier current of the wireless power receiver is greater than reference current, over-temperature state in which temperature of wireless power receiver is greater than reference temperature, and system error of wireless power receiver, and wherein a switch to protect wireless power receiver is turned off if the error state is over-voltage state.

PRIORITY

This continuation application claims priority under 35 U.S.C. § 120 toU.S. patent application Ser. No. 14/058,916, filed on Oct. 21, 2013 inthe United States Patent and Trademark Office, which claims priorityunder 35 U.S.C. § 119(a) to Korean Application Serial Nos.10-2012-0116528, 10-2012-0118538, and 10-2013-0050309, which were filedin the Korean Intellectual Property Office on Oct. 19, 2012, Oct. 24,2012, and May 3, 2013, respectively, the entire content of each of whichis incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to an apparatus and a method forefficiently transmitting emergency information in a wireless chargingnetwork, and more particularly, to a wireless power transmitter, awireless power receiver, and a method for transmitting emergencyinformation in a wireless charging network.

2. Description of the Related Art

Wireless charging techniques use wireless power transmission andreception to automatically charge a battery of an electronic device,e.g., a mobile phone, when the electronic device is located within apredetermined distance of a charging device, e.g., put on a chargingpad, without physically connecting the electronic device to aconventional charger.

The wireless charging techniques are broadly categorized into anelectromagnetic induction type using coils, a resonance type using aresonance phenomenon, and a Radio Frequency (RF)/Microwave radiationtype, which converts electrical energy into microwaves for transmission.

The electromagnetic induction technique transmits power between aprimary coil and a secondary coil. More specifically, when moving amagnet around a coil, a current is induced and electricity is generated.That is, a transmission end generates a magnetic field and a receptionend generates energy on behalf of the magnet, which is commonly referredto as an electromagnetic induction phenomenon.

The resonance technique wirelessly transmits power using aresonance-type power transmission principle over greater distances thanthe electromagnetic induction technique. Basically, electromagneticwaves are resonated containing electric energy, which is directlytransferred only to a device having a matching resonance frequency, andany unused portion is reabsorbed into an electromagnetic field insteadof spreading in the air.

Although various studies have been performed on the wireless chargingtechniques, when emergency situations occur in the wireless powerreceiver (or Power Reception Unit (PRU)), such as an over voltage, anover current, an over temperature, or a system error, the wireless powerreceiver should transmit emergency situation information to the wirelesspower transmitter (or Power Transmission Unit (PTU)). However, inconventional signal transmission protocols, no method has been proposedfor the wireless power receiver to transmit the emergency situationinformation to the wireless power transmitter.

SUMMARY OF THE INVENTION

Accordingly, the present invention is designed to address at least theproblems and/or disadvantages described above and to provide at leastthe advantages described below.

An aspect of the present invention is to provide a wireless powertransmitter, a wireless power receiver, and a method for transmittingemergency information transmission in a wireless charging network,wherein when an emergency situation occurs in the wireless powerreceiver of the wireless charging network, the emergency information istransmitted separately from a general message exchanging procedurebetween the wireless power receiver and the wireless power transmitter.

In accordance with an aspect of the present invention, a control methodof a wireless power receiver is provided. The method includestransmitting an advertisement signal to search for a wireless powertransmitter; receiving, from the wireless power transmitter, aconnection request signal to form a connection between the wirelesspower receiver and the wireless power transmitter, wherein theconnection request signal corresponds to the advertisement signal;receiving charging power from the wireless power transmitter; detectingan error state in the wireless power receiver while receiving thecharging power; generating an alert signal indicating the error state;and transmitting the alert signal to the wireless power transmitter,wherein the error state includes at least one of an over-voltage statein which a rectifier voltage of the wireless power receiver is greaterthan a reference voltage, an over-current state in which a rectifiercurrent of the wireless power receiver is greater than a referencecurrent, an over-temperature state in which a temperature of thewireless power receiver is greater than a reference temperature, and asystem error of the wireless power receiver, and wherein a switch toprotect the wireless power receiver is turned off if the error state isthe over-voltage state.

In accordance with another aspect of the present invention, a wirelesspower receiver is provided. The wireless power receiver includes aswitch; a communication unit configured to transmit an advertisementsignal to search for a wireless power transmitter, and receive, from thewireless power transmitter, a connection request signal to form aconnection between the wireless power receiver and the wireless powertransmitter, wherein the connection request signal corresponds to theadvertisement signal; and a power reception unit configured to receivecharging power from the wireless power transmitter; a controllerconfigured to detect an error state in the wireless power receiver whilereceiving the charging power, and generate an alert signal indicatingthe error state; wherein the communication unit is further configured totransmit the alert signal to the wireless power transmitter, wherein theerror state includes at least one of an over-voltage state in which arectifier voltage of the wireless power receiver is greater than areference voltage, an over-current state in which a rectifier current ofthe wireless power receiver is greater than a reference current, anover-temperature state in which a temperature of the wireless powerreceiver is greater than a reference temperature, and a system error ofthe wireless power receiver, and wherein the controller is furtherconfigured to turn off the switch to protect the wireless power receiverif the error state is the over-voltage state.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present invention will be more apparent from thefollowing detailed description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a block diagram illustrating a wireless charging systemaccording to an embodiment of the present invention;

FIG. 2 is a block diagram illustrating a wireless power transmitter anda wireless power receiver according to an embodiment of the presentinvention;

FIG. 3 is a block diagram illustrating a wireless power transmitter anda wireless power receiver according to an embodiment of the presentinvention;

FIG. 4 is a signal flow diagram illustrating operations of a wirelesspower transmitter and a wireless power receiver according to anembodiment of the present invention;

FIG. 5 is a flowchart illustrating operations of a wireless powertransmitter and a wireless power receiver according to an embodiment ofthe present invention;

FIG. 6 is a graph illustrating power amounts applied by a wireless powertransmitter over time according to an embodiment of the presentinvention;

FIG. 7 is a flowchart illustrating a control method of a wireless powertransmitter according to an embodiment of the present invention;

FIG. 8 is a graph illustrating power amounts applied by a wireless powertransmitter over time according to an embodiment of the presentinvention;

FIG. 9 is a flowchart illustrating a control method of a wireless powertransmitter according to an embodiment of the present invention;

FIG. 10 is a graph illustrating power amounts applied by a wirelesspower transmitter over time according to an embodiment of the presentinvention;

FIG. 11 is a block diagram illustrating a wireless power transmitter anda wireless power receiver according to an embodiment of the presentinvention;

FIG. 12 is a signal flow diagram illustrating a method of transmittingemergency situation information in a wireless charging network accordingto an embodiment of the present invention;

FIG. 13 is a flowchart illustrating an emergency informationtransmission procedure of a wireless power receiver according to anembodiment of the present invention;

FIG. 14 is a flowchart illustrating an emergency informationtransmission procedure of a wireless power receiver according to anembodiment of the present invention;

FIG. 15 is a flowchart illustrating an emergency information processingprocedure of a wireless power transmitter according to an embodiment ofthe present invention;

FIG. 16 is a flowchart illustrating a processing procedure of a wirelesspower receiver during an emergency situation, according to an embodimentof the present invention;

FIG. 17 is a flowchart illustrating an emergency information processingprocedure of a wireless power transmitter according to an embodiment ofthe present invention;

FIG. 18 is a flowchart illustrating an emergency information processingprocedure of a wireless power transmitter according to an embodiment ofthe present invention;

FIG. 19 is a flowchart illustrating an emergency information processingprocedure of a wireless power transmitter according to an embodiment ofthe present invention;

FIG. 20 is a flowchart illustrating a processing procedure of a wirelesspower receiver during an emergency situation, according to an embodimentof the present invention;

FIG. 21 is a flowchart illustrating a processing procedure of a wirelesspower transmitter during an emergency situation, according to anembodiment of the present invention; and

FIG. 22 is a signal flow diagram illustrating a method of transmittingand receiving a packet including emergency situation information in awireless charging network according to an embodiment of the presentinvention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

Various embodiments of the present invention will now be described indetail with reference to the accompanying drawings. In the followingdescription, specific details such as detailed configuration andcomponents are merely provided to assist the overall understanding ofthese embodiments of the present invention. Therefore, it should beapparent to those skilled in the art that various changes andmodifications of the embodiments described herein can be made withoutdeparting from the scope and spirit of the present invention. Inaddition, descriptions of well-known functions and constructions areomitted for clarity and conciseness.

FIG. 1 is a block illustrating a wireless charging system according toan embodiment of the present invention.

Referring to FIG. 1, the wireless charging system includes a wirelesspower transmitter 100, and wireless power receivers 110-1, 110-2, . . ., 110-n. For example, the wireless power receivers 110-1, 110-2, . . . ,110-n may be realized as mobile communication terminals, PersonalDigital Assistants (PDAs), Portable Multimedia Players (PDPs), smartphones, etc.

The wireless power transmitter 100 wirelessly transmit powers 1-1, 1-2,. . . , 1-n, e.g., in the form of electromagnetic waves, to the wirelesspower receivers 110-1, 110-2, . . . , 110-n, respectively. Morespecifically, the wireless power transmitter 100 wirelessly transmitsthe powers 1-1, 1-2, . . . , 1-n to authenticated wireless powerreceivers having undergone a predetermined authentication procedure.

The wireless power transmitter 100 performs two-way communication withthe wireless power receivers 110-1, 110-2, . . . , 110-n. Here, thewireless power transmitter 100 and the wireless power receivers 110-1,110-2, . . . , 110-n process or transmit/receive packets 2-1, 2-2, . . ., 2-n including frames.

When a resonance type wireless charging technology is used by thewireless power transmitter 100, distances between the wireless powertransmitter 100 and the wireless power receivers 110-1, 110-2, . . . ,110-n are approximately 30 mm or less. Further, when an electromagneticinduction type wireless charging technology is used by the wirelesspower transmitter 100, distances between the wireless power transmitter100 and the wireless power receivers 110-1, 110-2, . . . , 110-n areapproximately 10 cm or less.

The wireless power receivers 110-1, 110-2, . . . , 110-n wirelesslyreceive power from the wireless power transmitter 100 to chargebatteries therein. Additionally, the wireless power receivers 110-1,110-2, . . . , 110-n may transmit signals requesting wireless powertransmission, information for wireless power reception, stateinformation of the wireless power receivers, and control information forthe wireless power transmitter 100 to the wireless power transmitter100. Further, the wireless power receivers 110-1, 110-2, . . . , 110-nmay send messages indicating respective charging states thereof to thewireless power transmitter 100.

The wireless power transmitter 100 may include a display that displaysthe states of the wireless power receivers 110-1, 110-2, . . . , 110-n,based on the messages received from the wireless power receivers 110-1,110-2, . . . , 110-n. In addition, the wireless power transmitter 100may display expected times until the wireless power receivers 110-1,110-2, . . . , 110-n are completely charged.

The wireless power transmitter 100 may also transmit control signals tothe wireless power receivers 110-1, 110-2, . . . , 110-n, disablingtheir wireless charging functions. The wireless power receivers 110-1,110-2, . . . , 110-n having received the control signals for disablingthe wireless charging functions from the wireless power transmitter 100disable their wireless charging functions.

FIG. 2 is a block diagram illustrating a wireless power transmitter anda wireless power receiver according to an embodiment of the presentinvention.

Referring to FIG. 2, the wireless power transmitter 200 includes a powertransmission unit 211, a controller 212, and a communication unit 213,and the wireless power receiver 250 includes a power reception unit 251,a controller 252, and a communication unit 253.

The power transmission unit 211 supplies power to the wireless powertransmitter 200, and wirelessly supplies power to the wireless powerreceiver 250. The power transmission unit 211 may supply power in anAlternating Current (AC) waveform directly to the wireless powerreceiver 250, or supply the power in a Direct Current (DC) waveformthrough an inverter, which converts the DC power into AC power to besupplied to the wireless power receiver 250. The power transmission unit211 may be realized as a battery or as a power reception interface thatreceives power from an outside source, e.g., an outlet. Basically, thepower transmission unit 211 may be any device capable of wirelesslysupplying power.

In addition, the power transmission unit 211 may supply the AC power inthe form of an electromagnetic wave to the wireless power receiver 250.The power transmission unit 211 may additionally include a resonancecircuit (not shown), and thus, may transmit and receive anelectromagnetic wave. When the power transmission unit 211 includes aresonance circuit, an inductance L of a loop coil of the resonancecircuit may vary.

The controller 212 controls the overall operation of the wireless powertransmitter 200, e.g., through an algorithm, a program, or anapplication used by the controller 212, read from a storage unit (notshown). For example, the controller 212 may be a Central

Processing Unit (CPU), a microprocessor, or a mini computer.

The communication unit 213 performs communication with the wirelesspower receiver 250 through a predetermined method, e.g., using NearField Communication (NFC), Zigbee communication, infrared-raycommunication, visible light communication, Bluetooth communication, orBluetooth Low Energy (BLE). The communication unit 213 may also use aCarrier Sense Multiple Access with Collision Avoidance (CSMA/CA)algorithm.

The communication unit 213 transmits a signal for information of thewireless power transmitter 200, e.g., by unicasting, multicasting, orbroadcasting the signal.

Table 1 shows an example of a data structure of a signal transmittedfrom the wireless power transmitter 200 according to an embodiment ofthe present invention. The wireless power transmitter 200 may transmitthe signal at periodic intervals. Herein, the signal may also bereferred to as a notice signal.

TABLE 1 Rx to Report Se- (or Frame Protocol quence Network ScheduleNumber Type Version Number ID mask) Reserved of Rx Notice 4 bit 1 Byte 1Byte 1 Byte 5 bit 3 bit

In Table 1, the Frame Type field indicates the type of signal, i.e., anotice signal. The Protocol Version field indicates a protocol type ofthe communication, and in this example, is allotted 4 bits. The SequenceNumber filed indicates a sequential order of the corresponding signal,and in this example, is allotted 1 Byte. For example, the sequencenumber may increase by 1 in correspondence to transmission/receptionsteps of the signal.

The Network IDentifier (ID) field indicates a network ID of the wirelesspower transmitter 200, and in this example, is allotted 1 Byte. TheReceiver (Rx) to Report (or Schedule mask) field indicates the wirelesspower receivers that will report to the wireless power transmitter 200,and in this example, is allotted 1 Byte.

Table 2 shows an example of an Rx to Report (or Schedule mask) fieldaccording to an embodiment of the present invention.

TABLE 2 Rx to Report (Schedule mask) Rx1 Rx2 Rx3 Rx4 Rx5 Rx6 Rx7 Rx8 1 00 0 0 1 1 1

In Table 2, Rx1 to Rx8 correspond to wireless power receivers 1 to 8,respectively. Here, each wireless power receiver with a “1” in the Rx toReport (or Schedule mask) field is to report, i.e., Rx1, Rx6, Rx7, andRx8.

The Reserved field is reserved for later use, and in this example, isallotted 5 Bytes. The Number of Rx field indicates the number of thewireless power receivers around the wireless power transmitter 200, andin this example, is allotted 3 bits.

The communication unit 213 receives power information from the wirelesspower receiver 250. For example, the power information includes at leastone of a capacity of the wireless power receiver 250, a residual batteryamount, the number of times being charged, a used amount, a batterycapacity, and a battery rate.

As indicated above, the communication unit 213 may transmit a chargingfunction control signal for enabling or disabling the charging functionof the wireless power reception unit 251 of the specific wireless powerreceiver 250. Alternatively, the power information which will bedescribed in more detail may also include information such as lead-in ofa wired charging terminal, a conversion from a Service Availability (SA)mode to a Non-SA (NSA) mode, and release of an error situation.

The communication unit 213 may also receive a signal from anotherwireless power transmitter (not shown). For example, the communicationunit 213 may receive the notice signal of the frame shown in Table 1from the other wireless power transmitter.

Additionally, although the power transmission unit 211 and thecommunication unit 213 are illustrated in FIG. 2 as being differenthardware devices, the power transmission unit 211 and the communicationunit 213 may be embodied as a single hardware device.

The wireless power transmitter 200 and the wireless power receiver 250may transmit and receive different types of signals, such that thewireless power receiver 250 may join in a wireless power network managedby the wireless power transmitter 200, and charging may be performedthrough wireless power transmission/reception.

FIG. 3 is a block diagram illustrating a wireless power transmitter anda wireless power receiver according to an embodiment of the presentinvention.

Referring to FIG. 3, the wireless power transmitter 200 includes a powertransmission unit 211, a controller and a communication unit 212 and213, a driving unit 214, an amplifier 215, and a matching unit 216. Thewireless power receiver 250 includes a power reception unit 251, acontroller and a communication unit 252 and 253, a rectifier 254, aDC/DC convertor 255, a switching unit 256, and a loading unit 257.

The driving unit 214 outputs a DC power having a predetermined voltagevalue. The voltage value of the DC power output from the driving unit214 is controlled by the controller and the communication unit 212 and213.

The DC output from the driving unit 214 is output to the amplifier 215.The amplifier 215 amplifies the DC with a predetermined gain. Inaddition, the amplifier 215 may also convert the DC power into an ACpower, based on a signal received from the controller and thecommunication unit 212 and 213. Accordingly, the amplifier 215 mayoutput the AC power.

The matching unit 216 performs impedance matching. For example, thematching unit 216 adjusts the impedance viewed from the matching unit216 to control the power output with high efficiency and high power. Thematching unit 216 adjusts the impedance under the control of thecontroller and the communication unit 212 and 213. For example, thematching unit 216 includes at least one of a coil and a capacitor. Thecontroller and the communication unit 212 and 213 control a connectionwith the at least one of the coil and the capacitor to perform theimpedance matching.

The power transmission unit 211 transmits the AC power to the powerreception unit 251. The power transmission unit 211 and the powerreception unit 251 may be realized through a resonance circuit havingthe same resonance frequency. For example, the resonance frequency maybe 6.78 MHz.

The controller and the communication unit 212 and 213 communicate withthe controller and the communication unit 252 and 253 of the wirelesspower receiver 250, e.g., through a two-way frequency of 2.4 GHz.

The power reception unit 251 receives the AC charging power from thepower transmission unit 211.

The rectifier 254, e.g., a bridge diode, rectifies the wireless powerreceived in the power reception unit 251 into DC. The DC/DC convertor255 converts the rectified power with a predetermined gain. For example,the DC/DC convertor 255 converts the rectified power output 5V. Aminimum value and a maximum value of the voltage that may be applied maybe set in advance at a front end of the DC/DC convertor 255.

The switching unit 256 connects the DC/DC convertor 255 to the loadingunit 257. The switching unit 256 remains in an On or Off state under thecontrol of the controller and communication unit 252 and 253. Theloading unit 257 stores the converted power input from the DC/DCconvertor 255, when the switching unit 256 remains in the On state.

FIG. 4 is a signal flow diagram illustrating operations of a wirelesspower transmitter and a wireless power receiver according to anembodiment of the present invention.

Referring to FIG. 4, the wireless power transmitter 400 applies anelectric power in step S401. When the electric power is applied, thewireless power transmitter 400 is operating in a configuration mode instep S402.

The wireless power transmitter 400 enters a power save mode in stepS403. In the power save mode, the wireless power transmitter 400 mayapply different power beacons for detection according to respectiveperiods, which will be described below in more detail with reference toFIG. 6.

The wireless power transmitter 400 applies power beacons for detection404, . . . , 405, which may have different power values. All or some ofthe power beacons for detection 404, . . . , 405 may have enough powerto drive a communication unit of the wireless power receiver 450. Forexample, the wireless power receiver 450 may communicate with thewireless power transmitter 400 by driving the communication unit usingthe power beacons for detection 404, . . . , 405. In step S406, thewireless power receiver is in a Null state.

The wireless power transmitter 400 detects a load change through anarrangement of the wireless power receiver 450, and enters a low powermode in step S408).

In step S409, the wireless power receiver 450 drives the communicationunit based on the power having been received from the wireless powertransmitter 400.

The wireless power receiver 450 transmits a PTU search signal forsearching for a wireless power transmitter in step S410. For example,the wireless power receiver 450 may transmit the PTU search signalthrough a BLE based advertisement signal. The wireless power receiver450 may periodically transmit the PTU search signal, until receiving aresponse signal from the wireless power transmitter 400 or untilexpiration of a predetermined time.

When receiving the PTU search signal from the wireless power receiver450, the wireless power transmitter 400 transmits a PRU response signalin step S411. Here, the PRU response signal forms a connection betweenthe wireless power transmitter 400 and the wireless power receiver 450.

In step S412, the wireless power receiver 450 transmits a PRU staticsignal. For example, the PRU static signal indicates a state of thewireless power receiver 450, and requests joining in a wireless powernetwork managed by the wireless power transmitter 400.

In step S413, the wireless power transmitter 400 transmits a PTU staticsignal indicating a capacity of the wireless power transmitter 400.

In steps S414 and S415, the wireless power receiver 450 periodicallytransmits a PRU Dynamic signal including at least one informationparameter having been measured in the wireless power receiver 450. Forexample, the PRU Dynamic signal may include voltage information at arear end of a rectifier of the wireless power receiver 450. In stepS407, the wireless power receiver 450 enters a Boot state.

The wireless power transmitter 400 enters a power transfer mode in S416,and transmits a PRU control signal corresponding to an instructionsignal for allowing the wireless power receiver 450 to perform chargingin step S417. In the power transmission mode, the wireless powertransmitter 400 transmits charging power.

The PRU control signal transmitted by the wireless power transmitter 400may include information for enabling/disabling charging of the wirelesspower receiver 450, and permission information. For example, the PRUcontrol signal is transmitted when the wireless power transmitter 400wants to change the charging state of the wireless power receiver 450,or according to a predetermined period, for example, a period of 250 ms.

The wireless power receiver 450 changes a configuration in response tothe PRU control signal, and transmits a PRU Dynamic signal for reportingthe state of the wireless power receiver 450 in steps S418 and S419. Forexample, the PRU Dynamic signal transmitted by the wireless powerreceiver 450 includes at least one of a voltage, a current, a state ofthe wireless power receiver, and temperature information. In step S421,the wireless power receiver 450 is in an On state.

An example of a data structure of the PRU Dynamic signal is shown inTable 3.

TABLE 3 Field Octets Description Use Units Optional 1 Defines whichMandatory fields optional fields are populated V_(rect) 2 Voltage atMandatory mV diode output I_(rect) 2 Current at Mandatory mA diodeoutput V_(out) 2 Voltage at Optional mV charge/battery port I_(out) 2Current at Optional mA charge/battery port Temperature 1 TemperatureOptional Deg C. of PRU from −40 C. V_(rect) min dyn 2 V_(rect) lowOptional mV limit (dynamic value) V_(rect) set dyn 2 Desired V_(rect)Optional mV (dynamic value) V_(rect) high dyn 2 V_(rect) high OptionalmV limit (dynamic value) PRU alert 1 Warnings Mandatory Bit fieldReserved for 3 undefined Future Use (RFU)

As shown in Table 3, the PRU Dynamic signal includes selective fieldinformation, voltage information at a rear end of a rectifier of awireless power receiver, current information at a rear end of arectifier of a wireless power receiver, voltage information at a rearend of a DC/DC convertor of a wireless power receiver, currentinformation at a rear end of a DC/DC convertor of a wireless powerreceiver, temperature information, minimal voltage value information ata rear end of a rectifier of a wireless power receiver, optimal voltagevalue information at a rear end of a rectifier of a wireless powerreceiver, maximal voltage value information at a rear end of a rectifierof a wireless power receiver, and alert information (PRU alert).

An example of a data structure of the alert information (PRU alert) isshown below in Table 4.

TABLE 4 7 6 5 4 3 2 1 0 Over Voltage Over Over Charge TA TransitionRestart RFU Current Temperature Complete Detect Request

As shown in Table 4, the alert information (PRU alert) includes an OverVoltage field, an Over Current field, an Over Temperature field, aCharge Complete field, a Travel Adapter (TA) Detect field for wiredcharging terminal lead-in detection, a Transition field for SA mode/NSAmode transition, and a Restart Request field for a recharging request.

The wireless power receiver 450 performs charging through reception ofthe PRU control signal. For example, when the wireless power transmitter400 has enough power to charge the wireless power receiver 450, thewireless power receiver 450 transmits the PRU control signal to enablingcharging. For example, the PRU control signal may be transmitted eachtime the charging state is changed, at specific intervals, e.g., every250 ms, or when parameters are changed. The PRU control signal may alsobe transmitted within a predetermined threshold time, for example, 1second, even if the parameters are not changed.

During charging, the wireless power receiver 450 may detect an error.Thereafter, the wireless power receiver 450 transmits an alert signal tothe wireless power transmitter 400 in step S420. The alert signal may bea PRU Dynamic signal or a PRU alert signal.

For example, the wireless power receiver 450 may indicate the error inthe PRU alert field of Table 3 or may transmit a single alert signal(for example, a PRU alert signal) indicating the error. When receivingthe alert signal, the wireless power transmitter 400 enters a latchfault mode in step S422. The wireless power receiver 450 enters a Nullstate in step S423.

FIG. 5 is a flowchart illustrating operations of a wireless powertransmitter and a wireless power receiver according to an embodiment ofthe present invention.

Referring to FIG. 5, the wireless power transmitter starts driving instep S501. In step S503, the wireless power transmitter resets aninitial configuration. In step S505, the wireless power transmitterenters a power save mode. Herein, the power save mode may correspond toan interval in which the wireless power transmitter applies powers withdifferent power amounts to a power transmission unit.

FIG. 6 is a graph illustrating power amounts applied by a wireless powertransmitter over time according to an embodiment of the presentinvention.

For example, referring to FIG. 6, the power save mode corresponds to aninterval in which the wireless power transmitter applies seconddetection powers 601 and 602 and third detection powers 611, 612, 613,614, and 615 to the power transmission unit. The wireless powertransmitter may apply the second detection powers 601 and 602 accordingto a second period, for a second period of time. The wireless powertransmitter may apply the third detection powers 611, 612, 613, 614, and615 according to a third period, for a third period of time. Althoughthe power values of the third detection powers 611, 612, 613, 614, and615 are different from each other in FIG. 6, the power values of thethird detection powers 611, 612, 613, 614, and 615 may also be the same.

For example, the wireless power transmitter may output the thirddetection power 611, and then may output the third detection power 612having the same power amount as that of the third detection power 611.As described above, when the wireless power transmitter outputs thethird detection powers of the same magnitude, the power amount of thethird detection powers may correspond to a power amount capable ofdetecting the smallest wireless power receiver, for example, a wirelesspower receiver of category 1.

As another example, the wireless power transmitter may output the thirddetection power 611, and then may also output the third detection power612 having a power amount different from that of the third detectionpower 611. As described above, when the wireless power transmitteroutputs the third detection powers of different magnitudes, the poweramounts of the third detection powers may correspond to power amountscapable of detecting wireless power receivers of category 1 to 5. Forexample, the third detection power 611 may correspond to a power amountcapable of detecting a wireless power receiver of category 5, the thirddetection power 612 may correspond to a power amount capable ofdetecting a wireless power receiver of category 3, and the thirddetection power 613 may correspond to a power amount capable ofdetecting a wireless power receiver of category 1.

The second detection powers 601 and 602 may be powers capable of drivingthe wireless power receiver. More specifically, the second detectionpowers 601 and 602 may have power amounts capable of driving acontroller and a communication unit of the wireless power receiver.

The wireless power transmitter applies the second detection powers 601and 602, and the third detection powers 611, 612, 613, 614, and 615 to apower reception unit according to a second period and a third period,respectively.

When the wireless power receiver enters a wireless service area of thewireless power transmitter, the impedance as viewed from the wirelesspower transmitter changes. Accordingly, the wireless power transmittermay detect a change in the impedance while the second detection powers601 and 602, and the third detection powers 611, 612, 613, 614, and 615are applied. For example, the wireless power transmitter may detect achange in the impedance while the third detection power 615 is applied.

Referring again to FIG. 5, the wireless power transmitter detects anobject in step S507. When an object is not detected in step S507, thewireless power transmitter remains in a power save mode in step S505.

When an object is not detected, e.g., when an impedance change isdetected in step S507, the wireless power transmitter enters a low powermode in step S509.

In the low power mode the wireless power transmitter applies a drivingpower capable of driving the controller and the communication unit ofthe wireless power receiver. For example, referring again to FIG. 6, thewireless power transmitter applies a driving power 620 to a powertransmission unit. The wireless power receiver drives the controller andthe communication unit through reception of the driving power 620. Thewireless power receiver communicates with the wireless power transmitterusing the driving power 620.

For example, the wireless power receiver transmits and receives data forauthentication, and joins in a wireless power network, which thewireless power transmitter manages, based on the data. However, when aforeign object, i.e., not a wireless power receiver, is placed within acharging area of the wireless power transmitter, datatransmission/reception cannot be performed. Accordingly, the wirelesspower transmitter determines whether or not a new object placed within acharging area of the wireless power transmitter is a foreign object. Forexample, if a response is not received from an object for apredetermined period of time, the wireless power transmitter maydetermine the new object is a foreign object.

Referring again to FIG. 5, when an object has been determined to be aforeign object in step S511, the wireless power transmitter enters alatch fault mode in step S513. However, when the object is not a foreignobject in S511, the wireless power transmitter performs a joiningprocedure to possibly add the new wireless power receiver to thewireless charging network.

For example, referring again to FIG. 6, the wireless power transmittermay apply first powers 631 to 634 according to a first period. Thewireless power transmitter may detect a change in an impedance whileapplying the first powers.

Referring again to FIG. 5, when the foreign object is removed from thecharging area of the wireless power transmitter in step S515, i.e., thewireless power transmitter detects a change in impedance, the wirelesspower transmitter enters the power save mode in S517. However, when theforeign object is not removed from the charging area of the wirelesspower transmitter in S515-N, i.e., the wireless power transmitter doesnot detect the change in the impedance, the wireless power transmitterremains in the latch fault mode in step S513.

When the foreign substance has not been withdrawn, the wireless powertransmitter may inform a user that the wireless power transmitter iscurrently in an error state through an indication, such as a lampflicker and/or an alert sound.

For example, referring again to FIG. 6, after the foreign object isremoved, the wireless power transmitter applies second powers 651 and652, and third powers 661 to 665.

Additionally, the wireless power transmitter may have various otherconditions for entering the latch fault mode. For example, when thewireless power transmitter is cross-connected to a wireless powerreceiver, the wireless power transmitter may also enter the latch faultmode. A cross-connection occurs when a wireless power receiver currentlyconnected to another wireless power transmitter is joined in thewireless power network.

FIG. 7 is a flowchart illustrating a control method of a wireless powertransmitter according to an embodiment of the present invention.

Referring to FIG. 7, the wireless power transmitter starts driving instep S701. In step S703, the wireless power transmitter resets aninitial configuration. In step S705, the wireless power transmitterenters a power save mode. Again, during the power save mode, thewireless power transmitter applies different powers to a powertransmission unit.

FIG. 8 is a graph illustrating power amounts applied by a wireless powertransmitter over time according to an embodiment of the presentinvention.

Referring to FIG. 8, during the power save mode, the wireless powertransmitter applies second detection powers 801 and 802 and thirddetection powers 811, 812, 813, 814, and 815 to the power transmissionunit. The wireless power transmitter applies the second detection powers801 and 802 according to a second period, for a second period of time,and applies the third detection powers 811, 812, 813, 814, and 815according to a third period, for a third period of time. Although thepower values of the third detection powers 811, 812, 813, 814, and 815illustrated in FIG. 8 are different from each other, they may also bethe same.

The second detection powers 801 and 802 may be capable of driving thewireless power receiver, i.e., may be capable of driving a controllerand a communication unit of the wireless power receiver.

The wireless power transmitter applies the second detection powers 801and 802, and the third detection powers 811, 812, 813, 814, and 815 to apower reception unit according to a second period and a third period,respectively. When the wireless power receiver is placed in a chargingarea of the wireless power transmitter, impedance detected by thewireless power transmitter changes. The wireless power transmitter maydetect a change in the impedance while the second detection powers 801and 802, and the third detection powers 811, 812, 813, 814, and 815 areapplied. For example, the wireless power transmitter may detect a changein the impedance while the third detection power 815 is applied.

Referring again to FIG. 7, the wireless power transmitter detects anobject in step S707. When an object is not detected in step S707, thewireless power transmitter remains in the power save mode in step S705.

When the wireless power transmitter detects the object in step S707,i.e., when the impedance change is detected, the wireless powertransmitter enters a low power mode in step S709. In the low power mode,the wireless power transmitter applies a driving power capable ofdriving the controller and the communication unit of the wireless powerreceiver.

For example, referring again to FIG. 8, the wireless power transmitterapplies a driving power 820 to a power transmission unit. The wirelesspower receiver drives the controller and the communication unit throughreception of the driving power 820. The wireless power receivercommunicates with the wireless power transmitter using the driving power820. For example, the wireless power receiver transmits and receivesdata for authentication, and joins a wireless power network managed bythe wireless power transmitter, based on the data.

Referring again to FIG. 7, the wireless power transmitter enters a powertransmission mode for transmitting a charging power in step S711. Forexample, the wireless power transmitter applies a charging power 821, asillustrated in FIG. 8, which is transmitted to the wireless powerreceiver.

The wireless power transmitter may determine in the power transmissionmode whether or not an error occurs. For example, the error may be aforeign object placed in the charging area of the wireless powertransmitter, a cross-connection, an over voltage, an over current, anover temperature, etc. Accordingly, the wireless power transmitter mayinclude a sensing unit for measuring the over voltage, the over current,or the over temperature. For example, the wireless power transmitter maymeasure a voltage or a current of a reference point, and when themeasured voltage or current exceeds a threshold value, determines thatthe over voltage condition or the over current condition has beensatisfied.

Alternatively, the wireless power transmitter may include a temperaturesensing unit, which measures a temperature of the reference point. Whenthe temperature of the reference point exceeds a threshold value, thewireless power transmitter determines that the over temperaturecondition has been satisfied.

Although the error illustrated in FIG. 8 is a foreign object beingplaced in a charging area of the wireless power transmitter, it will beunderstood by those skilled in the art that the error is not limitedthereto, and the wireless power transmitter operates through similarprocesses for other errors, e.g., the cross-connection, the overvoltage, the over current, and the over temperature.

Referring again to FIG. 7, when an error does not occur in step S713,the wireless power transmitter remains in the power transmission mode instep S711. However, when an error occurs in step S713, the wirelesspower transmitter enters a latch fault mode in step S715. For example,the wireless power transmitter applies first powers 831 to 835, asillustrated in FIG. 8. Further, the wireless power transmitter output anerror indication of the latch fault mode.

When it is determined that the foreign object or the wireless powerreceiver has not been withdrawn, the wireless power transmitter remainsin the latch fault mode in step S715. However, when it is determinedthat the foreign substance or the wireless power receiver has beenwithdrawn, the wireless power transmitter enters the power save mode instep S719. For example, the wireless power transmitter applies secondpowers 851 and 851, and third powers 861 to 865, as illustrated in FIG.8.

FIG. 9 is a flowchart illustrating a control method of a wireless powertransmitter according to an embodiment of the present invention.

Referring to FIG. 9, the wireless power transmitter transmits a chargingpower to a first wireless power receiver in step S901. In step 903, thewireless power transmitter joins a second wireless power receiver into awireless power network managed by the wireless power transmitter. Instep S905, the wireless power transmitter transmits charging power toboth the first wireless power receiver and the second wireless powerreceiver. More specifically, the wireless power transmitter applies atotal sum of the charging powers that the first wireless power receiverand the second wireless power receiver require.

FIG. 10 is a graph illustrating power amounts applied by a wirelesspower transmitter over time according to an embodiment of the presentinvention. Specifically, FIG. 10 illustrates an embodiment for stepsS901 to S905 in FIG. 9.

Referring to FIG. 10, the wireless power transmitter remains in a powersave mode for applying second detection powers 1001 and 1002, and thirddetection powers 1011 to 1015. The wireless power transmitter detects afirst wireless power receiver, and enters a lower power mode formaintaining a detection power 1020. Thereafter, the wireless powertransmitter enters a power transmission mode for applying a firstcharging power 1030. The wireless power transmitter then detects asecond wireless power receiver, and joins the second wireless powerreceiver to the wireless power network. Thereafter, the wireless powertransmitter applies a second charging power 1040 corresponding to atotal sum of the charging powers required by the first wireless powerreceiver and the second wireless power receiver.

Referring again to FIG. 9, the wireless power transmitter may detect anerror occurrence in step S907. For example, the error may be a foreignobject placed in a charging area of the wireless power transmitter, across-connection, an over voltage, an over current, or an overtemperature as described above. When the error does not occur in stepS907, the wireless power transmitter maintains the second charging power1040, as illustrated in FIG. 10.

When an error occurs in step S907, the wireless power transmitter entersa latch fault mode in step S909. For example, the wireless powertransmitter applies first powers 1051 to 1055, as illustrated in FIG.10, according to a first period.

Thereafter, wireless power transmitter determines whether or not boththe first wireless power receiver and the second wireless power receiverhave been withdrawn in step S911. For example, the wireless powertransmitter may detect a change in an impedance while the first powers1051 to 1055 are applied. The wireless power transmitter determineswhether or not both the first wireless power receiver and the secondwireless power receiver are withdrawn, based on whether the impedancereturns to an initial numerical value.

When it is determined that both the first wireless power receiver andthe second wireless power receiver have been withdrawn in step S911, thewireless power transmitter enters the power save mode in step S913. Forexample, the wireless power transmitter applies second detection powers1061 and 1062, and third detection powers 1071 to 1075 according to asecond period and a third period, respectively, as illustrated in FIG.10.

When it is determined that both the first wireless power receiver andthe second wireless power receiver have not been withdrawn in step S911,the wireless power transmitter maintains the latch fault mode in stepS909.

As described above, even when applying the charging powers to aplurality of wireless power receivers, the wireless power transmittermay easily determine whether or not the wireless power receivers or theforeign object are withdrawn, when an error occurs.

FIG. 11 is a block diagram illustrating a wireless power transmitter anda wireless power receiver according to an embodiment of the presentinvention.

Referring to FIG. 11, the wireless power transmitter 1100 includes acommunication unit 1110, a power amplifier 1120, and a resonator 1130.The wireless power receiver 1150 includes a communication unit 1151, anApplication Processor (AP) 1152, a Power Management Integrated Circuit(PMIC) 1153, a wireless power Integrated Circuit (wireless power IC)1154, a resonator 1155, an InterFace Power Management (IFPM) IC 1157, aTA 1158, and a battery 159.

The communication unit 1100 communicates with the communication unit1151, for example, using BLE. The communication unit 1151 of thewireless power receiver 1150 transmits a PRU Dynamic signal having thedata structure of Table 3 to the communication unit 1110 of the wirelesspower transmitter 1100. As described above, the PRU Dynamic signal mayinclude at least one of voltage information, current information,temperature information, and alert information of the wireless powerreceiver 1150.

An output power value from the power amplifier 1120 is adjusted based onthe received PRU Dynamic signal. For example, when an over voltage, anover current, and an over temperature are applied to the wireless powerreceiver 1150, the power value output from the power amplifier 1120 maybe decreased. Further, when a voltage and a current of the wirelesspower receiver 1150 is less than a predetermined value, the power valueoutput from the power amplifier 1120 may be increased.

A charging power from the resonator 1130 is transmitted to the resonator1155.

The wireless power integrated circuit 1154 rectifies and DC-DC convertsthe charging power received from the resonator 1155. The wireless powerIC 1154 allows driving of the communication unit 1151 or charging of thebattery 1159 by using the converted power.

A wired charging terminal may be inserted in the travel adapter 1158.The wired charging terminal, such as a 30-pin connector or a UniversalSerial Bus (USB) connector, may be inserted in the travel adapter 1158,which charges the battery 1159 using power supplied from an externalpower source.

The IFPM integrated circuit 1157 processes and outputs a power appliedfrom the wired charging terminal to the battery 1159 and the PMIC 1153.

The PMIC 1153 manages wirelessly received power or power received via awire, and power applied to the respective elements of the wireless powerreceiver 1150. The AP 1152 receives power information from the PMIC1153, and controls the communication unit 1151 to transmit the PRUDynamic signal for reporting this.

The TA 1158 may be connected to a node 1156, which is connected to thewireless power IC 1154. When a travel connector is inserted in the TA1158, a predetermined voltage, e.g., 5V, may be applied to the node1156. The wireless power IC 1154 determines whether or not the travelconnector has been inserted in the TA 1158, through monitoring thevoltage applied to the node 1156.

FIG. 12 is a flow diagram illustrating a method of transmittingemergency situation information in a wireless charging system, accordingto an embodiment of the present invention. Because steps S401 to S421have already been described above for FIG. 4, a repetitive descriptionof these steps will be omitted here.

Referring to FIG. 12, when an emergency situation occurs in the wirelesspower receiver 450, the wireless power receiver 450 transmits a packetincluding emergency situation information to the wireless powertransmitter 400 in step S1201, and may enter an initial mode accordingto an embodiment of the present invention. The initial mode state maybe, for example, a load switch off state.

The wireless power transmitter 400 receives and processes the packetincluding the emergency situation information, and then stops thewireless power transmission.

Additionally, the wireless power transmitter 400 may transmit theemergency situation information to other wireless power receivers in thenetwork managed by the wireless power transmitter in step S1202, and mayenter the system in a reset mode (a switch off state).

If a communication link is continued, a connection can be continuouslymaintained. Further, when the wireless power transmitter 400 hasattempted to power off and reset, the wireless power receiver 450 mayset a new communication link from the wireless power transmitter.

According to an embodiment of the present invention, the emergencysituation information may include an over current situation (OCP), anover voltage situation (OVP), and an over temperature situation (OTP).

When the emergency situations (e.g., OCP, OVP, or OTP) occur, thewireless power transmitter 400 powers off a power module, and enters atransmission fault (Tx fault) mode according to an embodiment of thepresent invention.

An example of a format of a signal (message) frame for transmitting apacket including an emergency situation is shown below in Table 5.

In Table 5, a network ID refers to an address of a wireless powertransmitter network in which the wireless power receiver has joined, asession ID refers to an address of the wireless power receiver, and anemergency situation refers to a situation that has occurred in thewireless power receiver.

TABLE 5 Frame Sequence Network Emergency Type Number ID Case Session IDOctets 1 1 1 1 1

An example of the Emergency Case in Table 5 is shown below in Table 6.

TABLE 6 Emergency Case Value b7-b0 Description 0000 0000 Reserved 00000001 Over voltage occurred 0000 0010 Over current occurred 0000 0011Over temperature occurred 0000 0100 Rogue device detected 0000 0101-11111111 Reserved

An example of a BLE profile is shown in Table 7 below. A PRU Dynamicparameter including a PRU alert field may be transferred to the wirelesspower transmitter. The PRU Dynamic signal may be transmitted without arequest of the wireless power transmitter.

TABLE 7 Field Octets Description Use? Units Optional fields 1 Defineswhich Mandatory optional fields are populated VRECT 2 Voltage at diodeMandatory mV output IREG 2 Current at diode Mandatory mV output VOUT 2Voltage at Optional mV charge/battery port IOUT 2 Current at Optional mAcharge/battery port Temperature 1 Temperature of PRU Optional Deg C.from −40 C. VRECT_MIN_DYN 2 Minimum VRECT Optional** mV (dynamic value)VRECT_MAX_DYN 2 Maximum VRECT Optional** mV (dynamic value) PRU alert 1Warnings Mandatory * Bit field RFU 5 Undefined

An example of a detailed bit field for configuration of the PRU alertsignal in Table 7 is shown below in Table 8.

TABLE 8 7 6 5 4 3 2 1 0 Over Over Over Charge RFU RFU RFU RFU voltagecurrent temperature complete

Accordingly, when the emergency situation occurs in the wireless powerreceiver, the wireless power receiver may efficiently transmit theemergency situation information to the wireless power transmitteraccording to the embodiment of the present invention. For example, thewireless power receiver may also insert the emergency situationinformation into a specific field of the PRU Dynamic signal, which isperiodically transmitted to the wireless power transmitter, and may alsogenerate and transmit a separate PRU emergency signal to the wirelesspower transmitter in real time.

FIG. 13 is a flowchart illustrating an emergency informationtransmission procedure of a wireless power receiver (PRU) according toan embodiment of the present invention.

Referring to FIG. 13, the wireless power receiver (PRU) receives awireless charging power from a wireless power transmitter (PTU) in stepS1301, and transmits a PRU Dynamic signal to the PTU according to apredetermined period in step S1302.

When an emergency situation, such as an over voltage, an over current,an over temperature, etc., or a system error occurs in the PRU in stepS1303, the PRU transmits an emergency signal to the PTU according to anembodiment of the present invention in step S1304. Accordingly, when theemergency situation occurs, the PRU may rapidly transmit the emergencyinformation to the PTU, without waiting for a next PRU Dynamic signal.

FIG. 14 is a flowchart illustrating an emergency informationtransmission procedure of a wireless power receiver according to anembodiment of the present invention.

Referring to FIG. 14, a PRU receives a wireless charging power from awireless power transmitter (PTU) in step S1401, and transmits a PRUDynamic signal to the PTU according to a predetermined period in stepS1402.

When an emergency situation or a system error occurs in the PRU in stepS1403, the PRU adds emergency information to the PRU Dynamic signal totransmit that to the PTU according to an embodiment of the presentinvention (S1404). That is, when the emergency situation occurs, the PRUadds the emergency information to a specific data field in the PRUDynamic signal, and transmits the PRU Dynamic signal to the PTU.Accordingly, the PRU efficiently transmits the emergency information tothe PTU though the PRU Dynamic signal, without any additional signaling.

FIG. 15 is a flowchart illustrating an emergency information processingprocedure of a wireless power transmitter according to an embodiment ofthe present invention.

Referring to FIG. 15, when the PTU receives an emergency signal packetfrom a PRU in step S1501, the PTU stops the wireless power transmissionto the PRU in step S1502, and transmits the received emergencyinformation to other PRUs included in the wireless network in stepS1503. In step S1504, a system of the PTU is entered in a reset mode.

FIG. 16 is a flowchart illustrating a processing procedure of a wirelesspower receiver during an emergency situation, according to an embodimentof the present invention.

Referring to FIG. 16, the PRU transmits the emergency signal to the PTUin step S1601 and enters an initial mode state in step S1602. Theinitial mode state may be, for example, a load switch off state.

When the PTU supplying a wireless power to the PRU attempts to power offand reset after receiving the emergency information in step S1603, a newcommunication link from the PTU is set in step S1604. For example, theprocedure illustrated in FIG. 4 may be performed.

FIG. 17 is a flowchart illustrating an emergency information processingprocedure of a wireless power transmitter according to an embodiment ofthe present invention.

Referring to FIG. 17, a PTU transmits a wireless charging power to a PRUin step S1701. When an emergency situation occurs in the PTU in stepS1702, the PTU turns off a power transmission module of the PTU in stepS1703, and enters a transmission fault (Tx fault) state in step S1704.

FIG. 18 is a flowchart illustrating an emergency information processingprocedure of a wireless power transmitter according to an embodiment ofthe present invention.

Referring to FIG. 18, a PRU receives a wireless charging power from aPTU in step S1801. When an emergency situation occurs during wirelesscharging (S1802), the PRU changes a peripheral mode to a broadcast modein step S1803. In step S1804, the PRU transmits an Advertisement packetto other PRUs in a wireless charging network. In addition to performingone-to-one communication with the PTU, the PRU may transfer theemergency situation to other devices in the wireless charging network.For example, the Advertisement packet may include a target address, andemergency information.

FIG. 19 is a flowchart illustrating an emergency information processingprocedure of a wireless power transmitter according to an embodiment ofthe present invention.

Referring to FIG. 19, a PTU transmits a wireless charging power to a PRUin step S1901, and scans a packet transmitted from the PRU in stepS1902. The packet scanning may be performed according to a predeterminedperiod, and may also be performed every time a specific event occurs.

When an Advertisement packet from a specific PTU is received, based onthe packet scanning, in step S1903, information in the packet isidentified in step S1904, and a preset processing is performed accordingto an emergency procedure in step S1905.

FIG. 20 is a flowchart illustrating a processing procedure of a wirelesspower receiver during an emergency situation, according to an embodimentof the present invention.

Referring to FIG. 20, a PRU receives a wireless charging power from aPTU in step S2001. When an emergency situation occurs in step S2002, theperipheral mode is changed to the broadcast mode in step S2003.

When it is determined that the emergency situation corresponds to an OVPin step S2004, the emergency situation is considered more dangerous thanan emergency situation by an OCP or an OTP, and a load switch is turnedoff in step S2005 to stop the charging procedure. In step S2006, anemergency signal packet including the OVP is generated. In step S2008,the generated emergency signal packet is transmitted to the PTU.

However, when the emergency situation does not correspond to the OVP,but to the OCP or the OTP, which are considered less dangerous than theemergency situation by the OVP, the load switch is not turned off, andan emergency signal packet including the OCP and the OTP is generated instep S2007. In step S2008, the generated emergency signal packet istransmitted to the PTU.

Alternatively, the load switch off procedure in step S2005 and thepacket transmission procedure in step S2008 may be executed in adifferent order than illustrated in FIG. 20.

FIG. 21 is a flowchart illustrating a processing procedure of a wirelesspower transmitter during an emergency situation, according to anembodiment of the present invention. Specifically, FIG. 21 illustrates aprocedure of a PTU corresponding to the procedure of the PRU illustratedin FIG. 20.

Referring to FIG. 21, the PTU transmits a wireless charging power to thePRU in step S2101. When receiving an emergency signal packet from thePRU in step S2102, the PTU analyzes information included in the packet.

When it is determined that OVP information has been included in thepacket in step S2104, a latch fault mode is immediately entered in stepS2105, and a new configuration (reset) procedure is initiated in stepS2106.

However, when it is determined that the OVP information has not beenincluded in the packet in step S2104, and OCP information or OTPinformation has been included in the packet, the power transmission ismaintained, and a level of the transmitted wireless charging power islowered in step S2107. In step S2108, alert signals are transmitted tothe PRUs included in a wireless charging network of the PTU. In stepS2109, power tracking is performed through communication with therespective PRUs.

Alternatively, step S2107 and step S2108 may be executed in a differentorder than illustrated in FIG. 21.

FIG. 22 is a signal flow diagram illustrating a method for transmittingand receiving a packet including emergency situation information in awireless charging network according to an embodiment of the presentinvention.

When an emergency situation occurs while a wireless power transmissionprocedure is progressed according to the procedure having been describedabove with reference to FIG. 4, a wireless power receiver immediatelychanges a role thereof from a peripheral mode to a broadcasting mode. Anadvertisement packet may be transferred in the broadcasting mode, and anadvertisement channel may use channel numbers 38, 38, and 39.

For example, advertisement data may include a target address andemergency information, and may designate a target as a wireless powertransmitter. The advertisement data may include an over current, an overvoltage, and an over temperature of the wireless power receiver asemergency situation information. The wireless power transmitterperiodically or aperiodically serves as a scanner to acquire anadvertisement packet from the wireless power receiver, and performs anoperation for processing the emergency situation.

When an emergency situation occurs, in accordance with anotherembodiment of the present invention, the wireless power receiver changesthe role thereof to the peripheral mode or the broadcasting mode, andthen generates and transmits a packet including emergency situationinformation (e.g., OVP, OCP, and OTP) to the power transmitter. Thewireless power receiver turns off a load switch thereof, and generatesand transmits a packet including an emergency message (OVP) to thewireless power transmitter. After receiving the emergency message, thewireless power transmitter may enter a latch mode, and may newly performa configuration (reset).

When an emergency situation of the OCP or the OTP occurs in the wirelesspower receiver, the wireless power receiver generates and transmits thepacket including the emergency message (OCP or OTP) to the wirelesspower transmitter, and then reduces the power. The power is reduced aslow as a communication link with the wireless power receiver in whichthe emergency situation has occurred may be at least maintained, and forexample, the power may be configured between I_TX_Beacon_Min andI_TX_Beacon_Max.

The wireless power transmitter transmits an emergency message (a stateof the power receiver) to the wireless power receivers, and therespective wireless power receivers perform power tracking throughcommunication.

Referring to FIG. 22, after a configuration for a wireless chargingnetwork in the wireless power transmitter 400 in step S2201, thewireless power transmitter 400 transmits a PRU control signal to thewireless power receiver 450 in step S2203. In step S2202, the wirelesspower receiver 450 operates in a peripheral mode. The wireless powertransmitter 400 requests a PRU Dynamic parameter from the wireless powerreceiver 450 in step S2204, and the wireless power receiver 450transmits a PRU Dynamic parameter response in response to the request instep S2205.

When the power tracking is stabilized during wireless power transmissionin the wireless power transmitter 400 in step S2206, the wireless powertransmitter 400 instructs the corresponding wireless power receiver toenter a sleep possible mode in step S2207. Accordingly, thecorresponding wireless power receiver 450 operates in the sleep mode instep S2208.

The wireless power transmitter 400 transmits the PRU control signal andthe PRU Dynamic signal request to the wireless power receiver 450 insteps S2209, S2210, and S2211 However, as illustrated in FIG. 22, thewireless power receiver 450 does not receive the signals transmittedfrom the wireless power transmitter 400. Therefore, the wireless powerreceiver 450 determines that an emergency situation has occurred andterminates the sleep mode in step S2212. In step S2213, the wirelesspower receiver 450 shifts from the peripheral mode to a broadcast mode.

In steps S2214 and S2215, the wireless power receiver 450 begins totransfer the emergency signal to the wireless power transmitter 400according to the embodiment of the present invention. When the wirelesspower transmitter 400 enters a scanning mode to scan a packet in stepS2216, the wireless power transmitter 400 receives the emergency signaltransmitted from the wireless power receiver 450 in step S2217. Thewireless power transmitter having received the emergency signal performsan operation corresponding to the above-described emergency situation instep S2218.

According to the above-described embodiments of the present invention,when an emergency situation occurs in a wireless power receiver of awireless charging network, the wireless power receiver transmits theemergency information separate from a general message exchangingprocedure between the wireless power receiver and the wireless powertransmitter, which makes it possible to rapidly and efficiently copewith the emergency situation.

While the present invention has been particularly shown and describedwith reference to certain embodiments thereof, it will be understood bythose of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims and theirequivalents.

What is claimed is:
 1. A control method of a wireless power receiver,the method comprising: transmitting an advertisement signal to searchfor a wireless power transmitter; receiving, from the wireless powertransmitter, a connection request signal to form a connection betweenthe wireless power receiver and the wireless power transmitter, whereinthe connection request signal corresponds to the advertisement signal;receiving charging power from the wireless power transmitter; detectingan error state in the wireless power receiver while receiving thecharging power; generating an alert signal indicating the error state;and transmitting the alert signal to the wireless power transmitter,wherein the error state includes at least one of an over-voltage statein which a rectifier voltage of the wireless power receiver is greaterthan a reference voltage, an over-current state in which a rectifiercurrent of the wireless power receiver is greater than a referencecurrent, an over-temperature state in which a temperature of thewireless power receiver is greater than a reference temperature, and asystem error of the wireless power receiver, and wherein a switch toprotect the wireless power receiver is turned off if the error state isthe over-voltage state.
 2. The method of claim 1, further comprisingentering an initial mode state after transmitting the alert signal. 3.The method of claim 1, further comprising setting a new communicationlink with the wireless power transmitter, after transmitting the alertsignal, when the wireless power transmitter attempts to power off. 4.The method of claim 1, further comprising: changing to a broadcast modeafter transmitting the alert signal; and transmitting an advertisementpacket including a target address and the information of the errorstate.
 5. A wireless power receiver, comprising: a switch; acommunication unit configured to: transmit an advertisement signal tosearch for a wireless power transmitter, and receive, from the wirelesspower transmitter, a connection request signal to form a connectionbetween the wireless power receiver and the wireless power transmitter,wherein the connection request signal corresponds to the advertisementsignal; a power reception unit configured to receive charging power fromthe wireless power transmitter; and a controller configured to detect anerror state in the wireless power receiver while receiving the chargingpower, and generate an alert signal indicating the error state; andwherein the communication unit is further configured to transmit thealert signal to the wireless power transmitter, wherein the error stateincludes at least one of an over-voltage state in which a rectifiervoltage of the wireless power receiver is greater than a referencevoltage, an over-current state in which a rectifier current of thewireless power receiver is greater than a reference current, anover-temperature state in which a temperature of the wireless powerreceiver is greater than a reference temperature, and a system error ofthe wireless power receiver, and wherein the controller is furtherconfigured to turn off the switch to protect the wireless power receiverif the error state is the over-voltage state.
 6. The wireless powerreceiver of claim 5, wherein the controller is further configured toenter an initial mode state after the alert signal is transmitted. 7.The wireless power receiver of claim 5, wherein the controller isfurther configured to control to set a new communication link with thewireless power transmitter, after the alert signal is transmitted, whenthe wireless power transmitter attempts to power off.
 8. The wirelesspower receiver of claim 5, wherein the controller is further configuredto change to a broadcast mode, after the alert signal is transmitted,and wherein the communication unit is further configured to transmit anadvertisement packet including a target address and the information ofthe error state.